Vigilant！ Spam release may be fatal to your Web server

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A few days ago, a friend told us that opening our website was particularly slow, and he wants us to help him to do the site and provide website maintenance services, such feedback is really not a good thing for us, I started the reaction is that he is the first time to open our nets so slow, And I am here because often open their own website so feel not how slow. Then I press a look at the slower than the snail, I now realize the importance of the problem.

With my intuition about these questions, the first thing is to realize that the server is out of service, because our web site traffic is not going to increase much in these days, nor is it because our programs have failures like dead loops. At that time I felt very helpless, because the solution that I saw on the internet before that the problem of our own this does not appear, for example, we have not modified the site program so it is not likely to cause errors on the Web site program, and has not changed the configuration of the server is also unlikely to be a Web server configuration failure.

We looked at the server's resource consumption, found that the server's memory consumption at a normal level, and the server's CPU consumption has been full of 100%. Because the problem has arisen, and such a problem may let us lose the order, so we must solve it as soon as possible. So even though we know that the common solution on the Web is not about our problems, we try it, such as adjusting Apache configuration, checking Apache error logs, Apache and operating system conflicts, and so on, but it doesn't work. For example, we look at Apache logs without any errors, only our previous reboot and other actions of the warning or notification information.

We even tried to reboot Apache, and we found that the service CPU was up to 100%, and it didn't work if we restarted the server directly.

We've been in the investigation for one hours by this time, but there is no progress, so we thought about whether there is a large number of traffic attacks, but to view the log of our server's several major web sites found that there is no fixed IP frequent access to the site, it is not the kind of attack.

At this time we suddenly found that one of our WordPress Demo site error log more than the official site of our other operating status, of course, the error log volume reached hundreds of MB, this time we realized the problem. It's not that someone wants to attack our servers, or that our web site program is faulty, not our server configuration is wrong; The reason is that these advertising machines, the Internet, are now all over the place. Then I queried the size of the data, found that the demo station's comment data sheet up to 500MB, the number of records in the 300,000, and both are generated in these two days, and the corresponding number of user table records are also many.

So here is a thorough find the problem, that is, spam advertising information in the crazy release, in addition to the site to bring high access pressure, advertising in the process of publishing the software may be wrong to visit the site so that a lot of error log, In other words, the Web server Apache still needs to write the error log continuously, so it needs to consume a lot of CPU resources, so the server CPU resource is full and the website jam.

And as long as the problem solved after the simpler, that is to remove the demo station, or to the demo station set the appropriate permissions to reduce the release of spam information, so that the CPU usage immediately down to 20% below the normal level of recovery.

This has to praise the following Western Digital cloud server, because in such a case is only slow server, rather than direct downtime, this is also I do the West Digital agent for the first time so long the most real feel the quality of the product. In addition also spit the Web site on the Internet, is simply plagiarism is rife. For example, search to solve the httpd.exe process of Apache CPU too high after the occurrence of the content of the article is that several, and each may be thousands of sites claimed to be original. So here also remind everyone, the information on the net for reference only, the final still need to think about the summary, this will have more harvest.

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